1 /* 2 * net/sched/pedit.c Generic packet editor 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Jamal Hadi Salim (2002-4) 10 */ 11 12 #include <linux/types.h> 13 #include <linux/kernel.h> 14 #include <linux/string.h> 15 #include <linux/errno.h> 16 #include <linux/skbuff.h> 17 #include <linux/rtnetlink.h> 18 #include <linux/module.h> 19 #include <linux/init.h> 20 #include <net/netlink.h> 21 #include <net/pkt_sched.h> 22 #include <linux/tc_act/tc_pedit.h> 23 #include <net/tc_act/tc_pedit.h> 24 25 #define PEDIT_TAB_MASK 15 26 static struct tcf_common *tcf_pedit_ht[PEDIT_TAB_MASK + 1]; 27 static u32 pedit_idx_gen; 28 static DEFINE_RWLOCK(pedit_lock); 29 30 static struct tcf_hashinfo pedit_hash_info = { 31 .htab = tcf_pedit_ht, 32 .hmask = PEDIT_TAB_MASK, 33 .lock = &pedit_lock, 34 }; 35 36 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = { 37 [TCA_PEDIT_PARMS] = { .len = sizeof(struct tcf_pedit) }, 38 }; 39 40 static int tcf_pedit_init(struct nlattr *nla, struct nlattr *est, 41 struct tc_action *a, int ovr, int bind) 42 { 43 struct nlattr *tb[TCA_PEDIT_MAX + 1]; 44 struct tc_pedit *parm; 45 int ret = 0, err; 46 struct tcf_pedit *p; 47 struct tcf_common *pc; 48 struct tc_pedit_key *keys = NULL; 49 int ksize; 50 51 if (nla == NULL) 52 return -EINVAL; 53 54 err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy); 55 if (err < 0) 56 return err; 57 58 if (tb[TCA_PEDIT_PARMS] == NULL) 59 return -EINVAL; 60 parm = nla_data(tb[TCA_PEDIT_PARMS]); 61 ksize = parm->nkeys * sizeof(struct tc_pedit_key); 62 if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize) 63 return -EINVAL; 64 65 pc = tcf_hash_check(parm->index, a, bind, &pedit_hash_info); 66 if (!pc) { 67 if (!parm->nkeys) 68 return -EINVAL; 69 pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind, 70 &pedit_idx_gen, &pedit_hash_info); 71 if (IS_ERR(pc)) 72 return PTR_ERR(pc); 73 p = to_pedit(pc); 74 keys = kmalloc(ksize, GFP_KERNEL); 75 if (keys == NULL) { 76 kfree(pc); 77 return -ENOMEM; 78 } 79 ret = ACT_P_CREATED; 80 } else { 81 p = to_pedit(pc); 82 if (!ovr) { 83 tcf_hash_release(pc, bind, &pedit_hash_info); 84 return -EEXIST; 85 } 86 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) { 87 keys = kmalloc(ksize, GFP_KERNEL); 88 if (keys == NULL) 89 return -ENOMEM; 90 } 91 } 92 93 spin_lock_bh(&p->tcf_lock); 94 p->tcfp_flags = parm->flags; 95 p->tcf_action = parm->action; 96 if (keys) { 97 kfree(p->tcfp_keys); 98 p->tcfp_keys = keys; 99 p->tcfp_nkeys = parm->nkeys; 100 } 101 memcpy(p->tcfp_keys, parm->keys, ksize); 102 spin_unlock_bh(&p->tcf_lock); 103 if (ret == ACT_P_CREATED) 104 tcf_hash_insert(pc, &pedit_hash_info); 105 return ret; 106 } 107 108 static int tcf_pedit_cleanup(struct tc_action *a, int bind) 109 { 110 struct tcf_pedit *p = a->priv; 111 112 if (p) { 113 struct tc_pedit_key *keys = p->tcfp_keys; 114 if (tcf_hash_release(&p->common, bind, &pedit_hash_info)) { 115 kfree(keys); 116 return 1; 117 } 118 } 119 return 0; 120 } 121 122 static int tcf_pedit(struct sk_buff *skb, struct tc_action *a, 123 struct tcf_result *res) 124 { 125 struct tcf_pedit *p = a->priv; 126 int i, munged = 0; 127 u8 *pptr; 128 129 if (!(skb->tc_verd & TC_OK2MUNGE)) { 130 /* should we set skb->cloned? */ 131 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 132 return p->tcf_action; 133 } 134 } 135 136 pptr = skb_network_header(skb); 137 138 spin_lock(&p->tcf_lock); 139 140 p->tcf_tm.lastuse = jiffies; 141 142 if (p->tcfp_nkeys > 0) { 143 struct tc_pedit_key *tkey = p->tcfp_keys; 144 145 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) { 146 u32 *ptr; 147 int offset = tkey->off; 148 149 if (tkey->offmask) { 150 if (skb->len > tkey->at) { 151 char *j = pptr + tkey->at; 152 offset += ((*j & tkey->offmask) >> 153 tkey->shift); 154 } else { 155 goto bad; 156 } 157 } 158 159 if (offset % 4) { 160 printk("offset must be on 32 bit boundaries\n"); 161 goto bad; 162 } 163 if (offset > 0 && offset > skb->len) { 164 printk("offset %d cant exceed pkt length %d\n", 165 offset, skb->len); 166 goto bad; 167 } 168 169 ptr = (u32 *)(pptr+offset); 170 /* just do it, baby */ 171 *ptr = ((*ptr & tkey->mask) ^ tkey->val); 172 munged++; 173 } 174 175 if (munged) 176 skb->tc_verd = SET_TC_MUNGED(skb->tc_verd); 177 goto done; 178 } else { 179 printk("pedit BUG: index %d\n", p->tcf_index); 180 } 181 182 bad: 183 p->tcf_qstats.overlimits++; 184 done: 185 p->tcf_bstats.bytes += qdisc_pkt_len(skb); 186 p->tcf_bstats.packets++; 187 spin_unlock(&p->tcf_lock); 188 return p->tcf_action; 189 } 190 191 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a, 192 int bind, int ref) 193 { 194 unsigned char *b = skb_tail_pointer(skb); 195 struct tcf_pedit *p = a->priv; 196 struct tc_pedit *opt; 197 struct tcf_t t; 198 int s; 199 200 s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key); 201 202 /* netlink spinlocks held above us - must use ATOMIC */ 203 opt = kzalloc(s, GFP_ATOMIC); 204 if (unlikely(!opt)) 205 return -ENOBUFS; 206 207 memcpy(opt->keys, p->tcfp_keys, 208 p->tcfp_nkeys * sizeof(struct tc_pedit_key)); 209 opt->index = p->tcf_index; 210 opt->nkeys = p->tcfp_nkeys; 211 opt->flags = p->tcfp_flags; 212 opt->action = p->tcf_action; 213 opt->refcnt = p->tcf_refcnt - ref; 214 opt->bindcnt = p->tcf_bindcnt - bind; 215 216 NLA_PUT(skb, TCA_PEDIT_PARMS, s, opt); 217 t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install); 218 t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse); 219 t.expires = jiffies_to_clock_t(p->tcf_tm.expires); 220 NLA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t); 221 kfree(opt); 222 return skb->len; 223 224 nla_put_failure: 225 nlmsg_trim(skb, b); 226 kfree(opt); 227 return -1; 228 } 229 230 static struct tc_action_ops act_pedit_ops = { 231 .kind = "pedit", 232 .hinfo = &pedit_hash_info, 233 .type = TCA_ACT_PEDIT, 234 .capab = TCA_CAP_NONE, 235 .owner = THIS_MODULE, 236 .act = tcf_pedit, 237 .dump = tcf_pedit_dump, 238 .cleanup = tcf_pedit_cleanup, 239 .lookup = tcf_hash_search, 240 .init = tcf_pedit_init, 241 .walk = tcf_generic_walker 242 }; 243 244 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 245 MODULE_DESCRIPTION("Generic Packet Editor actions"); 246 MODULE_LICENSE("GPL"); 247 248 static int __init pedit_init_module(void) 249 { 250 return tcf_register_action(&act_pedit_ops); 251 } 252 253 static void __exit pedit_cleanup_module(void) 254 { 255 tcf_unregister_action(&act_pedit_ops); 256 } 257 258 module_init(pedit_init_module); 259 module_exit(pedit_cleanup_module); 260 261